Generally, a plurality of graphics (icons) each corresponding to one action are displayed on the display screen of the display device, and the operator selects a corresponding icon to command an action (hereinafter referred to as an object action). Conventionally, it was a common practice that a transparent touch sensor (touch panel) was installed on the front face of the display screen of the display device, so that the operator could command one action by selecting an icon displayed on the display screen and touching the icon on the touch sensor with a finger.
An operation switch for touching the icon is employed in the case of operating a navigation device or a car audio device while driving the car, for example, and has been already put to practical use.
FIG. 7 is a view showing a method for specifying an action in the conventional groping operation apparatus. In FIG. 7, there are four icons from object action 1 to object action 4 displayed on the display screen. When it is desired to command an object action 3, for example, the operator may touch an icon of the object action 3 on the touch panel (touch sensor) 17 with a finger to select the object action 3, so that a power switch of a specific audio apparatus can be turned on in accordance with an instruction of the object action 3.
However, since the display screen may shake within the moving car, it is difficult for the user to touch an icon indicating an object action correctly while driving the car. Therefore, the operator performs an operation while keeping an eye on the screen, which is a dangerous operation as the operation during the drive, and has difficulty in specifying the object action.
As means for solving such a problem, a device for informing the user of a selected icon (graphics) by uttering a sound that is different depending on the icon selected by the operator has been disclosed in Japanese Patent Application Laid-Open No. 4-309116 gazette.
However, with the device as disclosed in Japanese Patent Application Laid-Open No. 4-309116 gazette, there is the advantage of allowing for the selection operation without seeing the display screen, but if the selection operation of intent caused a failure, the selection operation had to be retried by confirming the failure in sound. Still, there was another problem that it took a lot of time to effect the selection operation in trial and error as described previously.
The present invention has been achieved in the light of the aforementioned problems, and it is an object of the invention to provide a groping operation apparatus that can specify an action to be commanded through the groping operation in reliable manner.